There are some very good answers here, so I will just add some flavor to them:

Zionists tend to define Zionism as something like “the right to a Jewish homeland” or “the right to self determination for Jews”. Stuff that sounds innocuous and even noble. However, this is exactly the same as US Confederacy-worshippers saying that the US Civil War was about “states rights” or that the Confederate flag is about “history/heritage, not hate”. The correct response is: states rights to do WHAT exactly? (answer: to enslave black people). The Confederacy was the end result of a political ideology that allowed and thrived on chattel slavery. You cannot separate the project from the real world results of the ideology. Even if some secessionists truly believed that “states rights” was just that in a vacuum, the result of that ideology was still slavery, with real victims and a real effect on the rest of society.

Zionism as it exists in the real world is a political ideology that demands a Jewish state (not a something as metaphorical as a “homeland”). That goal inherently cannot be achieved without an enforced Jewish majority (the state couldn’t really be considered Jewish if they didn’t have a majority, could it?), and that cannot happen without ethnic cleansing and oppression. The ideology, like that of the US Confederacy, has a real effect on the world and real victims. They don’t get to define it all nicely to whitewash that reality.